A computed tomography (CT) system according to a related art irradiates X-rays onto a subject to create X-ray projection images while rotating one X-ray source and synthesizes the images to create a three-dimensional image. In contrast, a tomosynthesis system that synthesizes plural X-ray projection images created by X-rays irradiated onto the subject at different angles from a plurality of X-ray sources has been studied and developed in recent years. The above system allows for rapidly creating tomosynthesis images of separated parts of a soft tissue with a radiation quantity lower than the CT system according to a related art.
However, the tomosynthesis system suggested in the related art is configured such that a plurality of X-ray sources are disposed in one vacuum chamber to be driven. In this case, even if only one of the plurality of X-ray sources malfunctions, the entire system should be disassembled to fix the malfunction, which causes difficulty in maintenance. It is also difficult to adjust the angles of the X-ray sources.